<script>
import { reactive, ref, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'

export default {
  name: 'GoodsImage',
  props: {
    images: { type: Array, default: () => [] }
  },
  setup () {
    //定义一个用于控制放大镜的显示状态的响应式变量
    const show = ref(false)
    //定义一个记录当前显示的图片索引的响应式变量
    const currIndex = ref(0)
    //定义一个引用，用于指向目标元素
    const target = ref(null)
    //定义一个用于记录放大镜位置的响应式对象
    const position = reactive({ top: 0, left: 0 })
    //定义一个记录背景图片位置的响应式对象
    const bgPosition = reactive({ backgroundPositionX: 0, backgroundPositionY: 0 })
    //使用useMouseInElement钩子，获取鼠标在元素内的坐标和是否在元素外部
    const { elementX, elementY, isOutside } = useMouseInElement(target)
    //监听鼠标位置和是否在元素外部的变化
    watch([elementX, elementY, isOutside], () => {
      if (isOutside.value) {
        show.value = false //如果鼠标在元素外部，隐藏放大镜
        return
      }
      show.value = true //如果鼠标在元素内部，显示放大镜
      //根据鼠标位置调整放大镜位置
      if (elementX.value < 100) {
        position.left = 0
      } else if (elementX.value > 300) {
        position.left = 200
      } else {
        position.left = elementX.value - 100
      }
      if (elementY.value < 100) {
        position.top = 0
      } else if (elementY.value > 300) {
        position.top = 200
      } else {
        position.top = elementY.value - 100
      }
      //根据鼠标位置调整背景图片的位置
      bgPosition.backgroundPositionY = -position.top * 2 + 'px'
      bgPosition.backgroundPositionX = -position.left * 2 + 'px'
      position.top += 'px'
      position.left += 'px'
    })
    return { currIndex, show, target, position, bgPosition }
  }
}
</script>

<template>
  <div class="goods-image">
    <div
      class="large"
      v-show="show"
      :style="[{ backgroundImage: `url(${images[currIndex]})` }, bgPosition]"
    ></div>
    <div class="middle">
      <img ref="target" :src="images[currIndex]" alt="" />
      <div class="layer" v-show="show" :style="[position]"></div>
    </div>
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex = i" :src="img" alt="" />
      </li>
    </ul>
  </div>
</template>

<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;
  ul {
    list-style: none;
    margin-top: 0px;
    padding-left: 0px;
  }
  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }
  .middle {
    width: 400px;
    height: 400px;
    position: relative;
    cursor: move;
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, 0.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  img {
    width: 100%;
    height: 100%;
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      margin-top: 0px;
      &:hover,
      &.active {
        border: 2px solid #27ba9b;
      }
    }
  }
}
</style>
